DE2559097A1 - DEVICE FOR MEASURING THE PARTICLE MASS PER UNIT VOLUME OF AN AEROSOL - Google Patents

Description

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DK. U. SCIJL-JJKL-HOPF tklkor. αγηομλιϊπά ι Munich

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SOCIETY FATIONALE DELIS FTTROLL'S DA-16662

D ^! ACUITiI IrIB

December 30, 1975

Priority νσ.Τΐ '* ■ ?. ^Λ . 197? France " ^r r. Τ? C ¹ ^"

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- a * solid Ko ι · ρ or, rocslLÖrper goii-nnt, öcr eir-o e>;. · ^ -, sum j'cil in front of eii ^ i- flat l'lektroia ivur AufnahKC 0 ^; · * Ϊί-ΐΐ-chen covered surface: 'c - e airrvreicl, and a voü dvr ίΛ ^' - nchif.d ^ iien Teilchoririynre αοΓ: ^) ΐ £ ·?. ^, C 'Lc ^ sonanrr ^ re ^ i ^ nt '':;. ΐ,

- 'MUi ¹ IoViAUi ₀ CiI Kun buttons eier 1: 1 e? Üiιεnzfic: j. -c) .i Vcrt.lc-ic ': ^ "! ri.it der iie ^ onan ^ frcouen ^ a ^ B fat rorpein same. cv- "· male, yeryleiehslibody known, ( ^! ez the same iempc -'- 'utuv · - U3.d rruekb'bdir. ^ ujigen is subject to v.'ie the I'esskbrper,

- Facilities zvin generating a rr.it acrorcl particles charged I-uftstroris in the direction of the flat lufrahau cler.tr ο ic hin, uno

- Einriclitun ^ en sua charging the epidemics r: it one of the poIc--

12s Bind various Voi'richtun ^ ei known which the Kigeni; Ci: rift beeti :: i: 'itcr body Y-sr-. Use, at a g ^; - ^ t bsner: geometric configuration having a definite Il £ Kon. In these devices, the deposition of particles of a traveling aerosol on a flat surface of a so-called "." Easkörpert veruri-eight by day! ·> -R "flow t-inew current high voltage of one-ϊ spits e.ulaufc :: uen metal; ätii "t κν.ν e'w.v :: irj ₍ ^ siu" csc - hv zv ^ Aohee aes pin loosened ^ nei surface of the measuring body _{ß f} the partially ror. of the flat surface

OÖS830 / 0568 BADORIQlNAt

sensing electrode covers ict, the tip of the pen has a distance from the flat surface which is greater than the discharge; = dry an electric arc in the air. In such devices, a comparison is made between the Rei-onansfreyjens Ces l'esskörperü and that of a comparison body r; employed, vrolck-er the same temperature and pressure lossLivS. ^ en au ^ g ^ c ^ tst Izτ ν; ie the sediment, on the surface of which, however, no precipitation of particles takes place.

Jn der νίΓεοΜκίΉ;: ;; known devices ΐκτ the ver ρ. li.ichnkkör ::! - i: i al ^ cf ^ pften T .'- ftstro: n p.-ig brought so that to bs: ^r . ".---- cktel · is, dac-j ei :: e "o ^ v ^ btOlievention of particles its Ζο:". ί: ± £ -; · \ τ-ι ± :. "" der L; rur; ssröer: i vird the air flow from ennsi- general α ". ι;: 'nuo of the circuit attached fjaugputnpe h £ .rvoi- £ err .. "fjr ... so dacc the D'jrcksats of such an arrangement duve] - v-.i ~ ic.vr.". i'i ^ l ^ e i'cl "\ nrikun ^ en the precipitation rate of the particles hecin- v-vrclcr- k;: · ::. ■■.

In the known devices the hetallotift is connected to the nc ^ iitiven kloi ^ ae of a dtrorinucj le hok-er voltage, and the flaclie Aufnnnhr-selek erode with a device for cutting the rosona'irirciusnz of the kessk body. This arrangement favors erosion of matter on the stylus and, consequently, changes in its configuration. This in turn results in fluctuations in the current intensity supplied, which generally results in a progressive deterioration in the impact performance of the particles. There is no stopping the current intensity fluctuations, since the high voltage energy source is not regulated in terms of current intensity, but rather in voltage.

The aim of the invention is to remedy this hang-up.

This goal is achieved with a device of the type described at the outset Art according to the invention achieved in that the Means for generating a charged with aerosol particles Air streams in the direction of the flat receiving electrode, and the means for charging the particles with a opposite to the polarity of the flat receiving electrode Polarity one with its axis perpendicular to the pick-up elec-

BATH ORIGINAL

-09830/0568

tr ode and at a distance between ~ j> and 15 rm from this, which is connected to a: le-re poritive I'olarity of a power source, which supplies a direct current of very high ορεηηια ·; -, while the flat pick-up electrode ta hinrichte.gen zv :: - read π er: o.ct Resonai '.'. '. f ^ enuenr: de: Lleeskc-rpers prg- e sr ¹ "": ν per in eJ ;; G ^ir i : ■ - ■ '■ ": r.ti.ft gJ'-lehaehsigen canal r. ^v ordered rind, del ·; Gogenaij: i-" ϊ h " ec ^ kr> j ::; l, which eli.e next to the Gi-i't / .o of the .stift-ε c-ijvnüi'idcJide Lurtzuführleitun ^ nxö. a g.lcooh & chfjir ':.''^ ^! ' ! St if χ r · -: '"the side facing away from ui-ac an ^ eord) el- :, after ru ^ -sej-! V ^; i.1ci: uü Cfi'-iuir, and hesshäne ₅ Ketallstif t and: *. · '.- tr 1 :: ·. ■ ·: ??.! zucan ^ oi form an Ilessftelle.

Indians: ran ö ^ n Btift niit öor positive YAc we ν er "hi; ^ C- (rl, wins the air flow already observed in the he ^ arrtcr · t'n. ₍ ; En tu observing air flow; ^, '' electric 'l ^v iu' ^: ^ rr ..-} - ri. such vj < strength, f .'-. es it not: ^ ehr noti £ Ii, eir a ^ c ', p "-'. pc au vnr «Will3i, why no r not, rk c-" r -; t- or γϊ £; τ: -_ - <\ - 3 ;; /: _ 'rd Gi:': ·· Ueg ro ^ o is chosen that r. The I pd eve '-' liTstf-. Rinimal sird.

Since the pen en the positive I * le; '.: e der ^ ci'.O-.r.-r ^ .j-.n-un / x'-uc-lla is connected, the ürderic. ^ Oij may be; f> r] 'o: fi ^ ur ·. ti o :: very long sara on, and da-ait ες'-ch dm: u "back ^ uführenden Btromstärkeschwi nkur ^ s" Γί: on the ΙΓ punched the 3hiederschla £ sleistung to opti Center, but is also a Kegelung amperage of the supplied en otro-is provided.

The solid Vergleichskör via is preferential as oll grain sia in a \ ⁷ closed housing, the =: · so-called comparison housing, arranged having a) i the Ilesskar.ai analog channel, or a same "" CHARACTERISTICS wj e of r-.ufweieenc .en channel, the hip supply line and the axial Dffn ^^ ng are closed in these different versions.

If the comparison housing consists of a cell ", which has the same characteristics as a less cell ait more closed Air supply line and closed axial opening, it is possible to alternate each of the two cells once

098 30/0 58 8

BATH ORIGINAL

to be used as a measuring cell or comparison trowel. This makes The device is very versatile in its application and offers the beetenllöj-loan options for regulation and comparison of the Measurement results.

In a preferred embodiment, for 3 of the different options of the comparison cell, the direct current source is provided with a device for regulating the current intensity of the strobe. which particular devices sun keeping constant the current supplied unifasßt "Such a regulating device is for example in the ar fr:% ό ε is h patent application Ur. 7! 5.0064'I- dec of applicant's vo: c 10.1,1975.

The invention is illustrated below with the aid of an exemplary embodiment, since it is shown in FIGS. 4 to 7, in more detail described and explained. j? y. 1 to 3 refer to calibration the state of the art. IJs aeigen:

- Fig. 1 shows a known device axing one according to the T.'ess- body arranged comparison body.

- Pig. 2 shows a further known device with an after the measuring body arranged in front; corpses.

- Fig. 3 the "corona effect" with negatively charged ": et allst if t.

- Fig. 4 shows the F, orona effect with a positively charged metal pen.

5 shows the control of the Eorona effect by means of a Resistance.

6 shows a longitudinal section through the Iess cell.

7 shows a cross section through the measuring cell and comparison cell.

In Figs. 1 ... and 2 are schematic !! two known devices for measuring the particle mass of an aerosol per unit volume shown. Both figures show a metal pin 1, with a perpendicular to a flat surface 2 of a T.Tesckörpers 3 arranged axis, the surface 2 is partially covered by a flat receiving electrode 4. The body 3 has a resonance.freq.uen,?; on that may vary, though the configuration of the Lesskörpers 3 changes, in particular as a result the deposition of particles on the flat electrode 4,

The pin 1 is connected to the negative terminal of a power source 5 with a very high voltage. The flat electrode 4

809830/0568 bad ohkjinal

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is with a facility?, u ^r : i Hessen der Resori-Jisfreoi'crir; of the measuring body s 3, namely deu Ossiilator 6, ν er blind en.

The outermost tip 7 of the pin 1 h-.it is a distance d_ from the flat electrode; this distance is large ^ is the Ent laduia _o s path of an electric arc in the air at the applied -loche parmung.

Pig. 1 ctellt cii.e version car, in which ö.er pin 1 and the -: eGS body 3 are arranged in a ku this equiaxed I'et.skanal C. The i'easkanal 8 v / eist one after κ t the tip 7 of the pin 1 debouching Luftzuf U ar line 9 and in a volumetric pump 11 is attached to the outside rnmclende opening 10 _t. In this embodiment, a comparative body 3 'in ileeskanyl C is arranged between the!' Yarn body 3 and the puncture 11.

The pin 1 is found in FIG. 2 in the same arrangement with its tip 7 at a distance d_ sur flat Ilektrods 4, the 52UQ part of the flat surface 2 of the body 3 covers. On the other hand, here the equal body Oi 3 'is in some of the Yergloich canal 8 'attached, the lateral extension of the l'essk an al s 3, with which he gangs part 12 in via a lib Connection.

In the remarks after Pig. 1 and 2 is the metal pin 1 on the negative clergy of a power source. 5 is connected to a very high voltage, and the pickup electrode 4 covering a rope of the flat surface 2 of the junction body 3 is connected to an oscillator 6. A pick-up electrode 4 ¹ covering part of the surface 2 ^{f of} a matching body 3 'is connected to an os?; Illator 6 ¹ .

These two remarks give rise to the following considerations Reason:

• 1) The reference body, the one in the air flow behind the measuring body is arranged, receives those aerosol particles that could not settle on the eating body, or from this were ripped off.

2) The number of a negative polarity for the "Tetallstift" is decisive for its rapid wear, which is shown by an increase in the radius of curvature of its tip. the

609830/0 56 8

Fluctuations in current between the pen and the electrode make themselves in general "noticeable in an increasing Deterioration in the precipitation performance of the particles on the electrode.

3) Fig. 3 schematically shows the course of the streamlines 14 "the so-called" corona effect "between a pin 1 of negative polarity and a flat electrode arranged at right angles to the pin axis. These electric streamlines 14, shown in dashed lines, occupy a space of bell-shaped, expansive shape, and the air surrounding the tip of the pen flows past the periphery of the bell-shaped, expansive space in the form of fine air streaks 15, shown in dotted lines. The air strikes the flat surface from outside its central zone, and the aerosol particles carried by the air, being carried away by the corona effect, are deposited on the periphery of the flat surface; a part of it can and will even be deposited outside the electrode thus not covered.

The Pig. 4 shows schematize)! the course of the electrical. Streamlines 14 _? In the so-called corona effect, between a metal pen of positive polarity and a flat electrode arranged at a right angle to the pen axis, which run in the immediate vicinity of the solder precipitated from the tip of the pen onto the electrode. The air surrounding the pen flows in this example in the form of the dotted air streaks 15 along the streamlines; it meets the electrode in the immediate vicinity of its middle zone and then deviates towards the periphery. With this arrangement, the aerosol particles can settle very regularly over the middle zone of the flat receiving electrode.

In search of an optimal distribution in the deposition of the aerosol particles on the sensitive electrode of the ilex body, experiments were carried out with the device according to FIG . It should be noted that the strength of the electric wind is now sufficient to guarantee a throughput of around 1 liter per minute. The suction tape at the exit of the Hess ze Ue becomes abundant

609830/0568 ^S '

In order to keep the air throughput at a regular 3 Corona effect are stabilized according to the current strength; for this purpose there are two complementary Iassnahnon intended. First, as shown in FIG. 5, Y / is resistance in the size of 10 Hegaohu in row v, ur Si: lead line to the peak I-le t allst if t switched, the current strength fluctuations very short period of time. Furthermore is a Device such as the one in the French patent application Hr, 75.00644 of the applicant from 10.1.1975 described Strorastärke-StabiÜF.ator intended for very high voltages, the keeps the amperage at a certain, fixed 17 t and eliminates dull deviation.

Fig. 6 is a longitudinal section through a flow cell A or A comparison table B of a new device sur; 'esnung the particle mass per unit volume of an aerosol.

In a building block 17 made of plastic material with holiesa more specific.! Line resistance and high dielectric constant, such as desi in trade under the name "Altuglas" guided 'material is a cylindrical ileus canal 8 drilled. The iTesskanal unfr. Has several coaxial measurements, namely: a section 8a. whose lurchnesser in proportion is small to its length, and in which a '-'et allst if t 1 is concentric and is fastened tightly; a section 8b, the diameter of which is large in relation to its length, and which forms a discharge chamber in which the measuring body 3, consisting of a thin piezoelectric quartz plate arranged perpendicular to the axis of the channel is, and finally a section 8c, the diameter of which corresponds approximately to that of the section Sa, and over a Opening 10 opens outwards.

. The pin 1 comprises several cylindrical sections, from at least one of which, namely 1a, has the same diameter as the channel Sa has, and closes at one end in a conically pointed section 1b made of steel, \ Yolfrani or stainless steel, with the outermost. Tip preferably consists of tungsten.

609830/0568

Per Geliäuseblock 17 has the shape of a par all =! Flat, clr.s a prismatic cutout 18 on v / eist to facilitate the drilling of an air supply line 9 su, which in the section 8a next to the conically pointed end 7 de, y pointed AbG chn i11ε 1b mouth t.

The Gehäuf-ebloek 17 is the original lighter original of the Susar: nienbau £? or the dismantling of the boiler or the comparative trowel divided into two parts 19 and 20, namely by the liloeiie xx cutting through the upper housing block, which are shown in Jf-ig. 6 is the JÜttel level of the Sntladekanter 8b. In your assembly, the arrows 19 and 20 are positively connected to one another by means of screws (not shown).

The metal pin 1 is tilted to a positive polarity terminal a power source 5 holier voltage connected through a laid through the part 19 electrical conductor 21, the π: it the Pin is in contact via one of its cylindrical sections.

By means of a support part 22, the discharge number 8b is held in the JJittelzoiie per Tts Gk or per 3. This Uesskörper v / eis one of the ötiftspitEe 7 opposite, your surface 2 on. A flat electrode for receiving the aerosol particles is attached to a wedge of its surface, namely the central part. The flat electrode 4 and an electrode 23 attached to the reverse side are connected to an oscillator 6 via electrical conductors 24 and 25.

Fife 7 is a cross-section according to ^T -; level xx through a "device which consists of a combination of a flow cell A with an adjacent flow cell, the comparative cell B. Kan recognizes the cross-section through the discharge cells 8b-A of the cell a plate with a 3 _Λ circular TJmfangs of piezoelectric quartz, and the cross-section 8b-B through the cell B with the likewise circular plate 3 ",

On each measuring body 3> _{A <} or. 3 · ^ is opposite the pin 1, or 1 ,, coaxial to the corresponding measuring body 3. or 3 ,,

-'J A -b

a circular electrode 26 »or 26-n attached. On the side facing away from the pin 1 or I _x , there is a circular one

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Electrode 27 ″ or 27p also coaxially to the corresponding measuring body 3, for example. 3y> noted. The electrode plates 26 _Λ , 26 _B , 27 _A , 27 _B are on the conductors 25 _A , 24- _ß , 24. _γ , 25 _B to the cell A or v /. B associated oscillators 6. bsw. 6- connected.

The outputs of the Cs cd. 11 at ors G ₁ and 5p are connected to a Frenuenzttischstufe 28, whose output is connected to a j? Renuenznesser 2S, which entv / edsr a storage scale or a device for recording the difference in the resonance frequency between the bodies 3a and 3 ,, contains.

In an embodiment corresponding to the preceding description, the gate direction to the tying solution of the particle riar; ce per volume unit of an aerosol in which the pen was exposed to a voltage of +10,000 volts, and with a distance of d = 15 nra between the tip of the "etallstifts v.nä the" lesselectrode, a throughput of 1 liter of air per wire generated by the electrical system was achieved.

The size of the collapsed aerosol particles is between 0.01 and 50 microns. The comparative measurements between the resonance frequency of the iless body and that of the reference body become continuous or at certain, fixed intervals pre-genonines.

The accuracy of the indications obtained is in the order of magnitude from a Kertz,

The embodiment described above, which produced the results enumerated above, as an example, does not limit the invention.

309830/0568

Claims (1)

Claims .i device for reading the particle mass per volume unit of an aerosol, consisting of: - a solid body, called the measuring body, which is an elementary, Part of a flat electrode for picking up the particles has a covered surface, and has a resonance frequency that depends on the particle mass deposited, - Facilities i? -U "i '-lessen the resonance frequency of the fixed Body, called the body, especially by comparison with the resonance frequency of a solid body with the same Jier characteristics, Called reference body, which has the same temperature and is subject to pressure conditions like the measuring body, - Means for generating one charged with aerosol particles Air s tr on) s in the direction of the flat receptacle e IeIi-trode there and ~ Means for charging the particles with one of the polarities polarity opposite to that of the jiufnahnie electrode, characterized in that the facilities for generating an air stream charged with aerosol particles in the direction of on the flat receiving electrode, εοτ / ie the facilities to charge the particles with either polarity of the receiving electrode opposite polarity one with its axis perpendicular to the receiving electrode and at a distance of 3 have up to 15 mm of this arranged metal pin, the is connected to a terminal of positive polarity of a current source which has a very high voltage DC supplies while the flat receiving electrode to facilities zxim. Measure the resonance frequency of the boiler body connected is, and the ketall pin as / ie the measuring body in a canal coaxial with the pen, the so-called! iesskanal, are arranged, which is a next to the tip of the pen opening air supply line and an equiaxed to the pin on the side facing away from this, has outwardly opening opening, and measuring body, Iletallstift and measuring channel together form a Hess cell. 2. Apparatus according to claim 1, characterized in that, ss the comparison body is housed in a completely closed housing, the so-called comparison housing. 6 09830/0568 5. Apparatus according to claim 2, characterized in that the comparison housing has a channel analogous to the I.esskanal on v / eist, its air supply and axial opening are closed. 4. Door direction according to claim 2, characterized in that the comparison nozzle has a channel with the same characteristics as the I.Iesskanel has, its air supply line and axial of fining are closed. 5. Apparatus according to claim 2, characterized in that mark the comparison housing a cell with the same "" ' vie the J.'zessselle aufv / eiet, its air supply line and axial opening are closed. 6. The device according to claim 1, characterized in that the direct current source is provided with a device for regulating the current strength of the supplied current, which in particular has a device for stabilizing the supplied current strength u -.;: Iaest. 7. Apparatus according to claim 6, characterized in that the comparative steroid in a completely closed C-ε-housing. the so-called Yergleichs, -ehäiU; e, accommodated is wrong. 8. Apparatus according to claim 7, characterized in that the comparison housing is an analog channel to the ilesskanal has, the air supply line and axial opening are closed. 9. The device as claimed in claim 7, characterized in that the comparing device rides a channel using the same channels how the Hess Canal weeps, its. Air supply line and axial opening are closed. 10. The device according to claim 7, characterized in that the comparison housing · a cell with the same IT cables . How the measuring cell has its air supply line and axial opening are closed. Π 09830/0568 / ι Blank page